Various systems exist to retrofit vehicles such as buses with air conditioning units, including units that are roof-mounted. Such vehicles frequently have curved roofs, and the radius of curvature of the roof may vary between vehicle models. Typically, the installation of the above-mentioned roof-mounted air conditioning systems requires one or more time-consuming procedures to compensate for the roof's curvature, which may raise the cost of installation. For example, some systems require the insertion of a substantial portion of the system into the vehicle's roof (i.e. by removing a portion of the roof's outer layer, and potentially modifying the internal structural components of the roof). Further, some systems require the installation of various supporting structures within or on the outside of the roof to support the air conditioning system.
Some conventional roof-mounted air conditioning systems attempt to reduce the need for the accommodations mentioned above by reducing the overall size of the system, particularly the width of the system (e.g. in the direction perpendicular to the length of the vehicle). However, such reductions in size can negatively affect air flow through the system, as well as render system maintenance difficult.